install-monitor.go

package main

import (
        "encoding/json"
        "log"
        "net/http"
        "strings"
        "time"
)

type SetupInfo struct {
        Status  string
        Updated time.Time
}

func Info(status string) *SetupInfo {
        return &SetupInfo{
                status,
                time.Now(),
        }
}

func (i *SetupInfo) Update(status string) {
        if status != i.Status {
                i.Status = status
                i.Updated = time.Now()
        }
}

var stata map[string]*SetupInfo

const address = "0.0.0.0:3030"

func Addr(s string) string {
        i := strings.LastIndex(s, ":")
        if -1 != i {
                return s[:i]
        } else {
                return s
        }
}

func setOrUpdate(remoteAddr string, status string) {
        slot := Addr(remoteAddr)
        if nil == stata[slot] {
                stata[slot] = Info(status)
        } else {
                stata[slot].Update(status)
        }
}

func Start(w http.ResponseWriter, req *http.Request) {
        log.Printf("Install on %s has started", req.RemoteAddr)
        setOrUpdate(req.RemoteAddr, "started")
}

func Post(w http.ResponseWriter, req *http.Request) {
        log.Printf("Install on %s has reached the post-install stage", req.RemoteAddr)
        setOrUpdate(req.RemoteAddr, "post-install")
}

func Done(w http.ResponseWriter, req *http.Request) {
        log.Printf("Install on %s has completed", req.RemoteAddr)
        setOrUpdate(req.RemoteAddr, "done")
}

func Get(w http.ResponseWriter, req *http.Request) {
        w.Header().Set("Content-type", "application/json")
        encoder := json.NewEncoder(w)
        encoder.Encode(stata)
}

func main() {
        stata = make(map[string]*SetupInfo)
        http.HandleFunc("/install/start", Start)
        http.HandleFunc("/install/post", Post)
        http.HandleFunc("/install/done", Done)
        http.HandleFunc("/get", Get)
        log.Printf("Listening on %s\n", address)
        http.ListenAndServe(address, nil)
}